Undefined behavior — evil or blessing?
- What is UB? Examples.
- similar concepts: unspecified behavior, implementation-defined behavior, conditionally supported
- What are the consequences of UB in a program?
- Why does C and C++ resort to undefined behavior?
- Advanced: Using UB for optimization
[intro.abstract]/4
Certain other operations are described in this document as undefined (for example, the effect of attempting to modify a const object). [Note: This document imposes no requirements on the behavior of programs that contain undefined behavior. — end note]